This invention relates to template devices and has particular utility as an antisera template in an immunofixation electrophoresis system.
Immunofixation electrophoresis, referred to as IFE, is well-known as a two-stage procedure for detecting the presence of certain proteins in human serum, urine or cerebral spinal fluid. The procedure involves, as a first step, protein fraction resolution by electrophoresis. As a second step, the soluble antigen in each protein fraction is allowed to react with its antibody. The resultant antigen-antibody complexes will precipitate, at a rate dependent upon the proportion of the reactants, temperature, salt concentration and pH. The antigen-antibody complexes are then visualized by staining.
The IFE process is described in greater detail in Gebott et al, U.S. Pat. No. 4,668,363 issued May 26, 1987, which is hereby incorporated by reference. Apparatus and chemicals for performing IFE have been marketed for some time by Helena Laboratories Corporation of Beaumont, Tex.
Typically, a specimen from a single patient is diluted and then placed in multiple sample or application areas (also referred to as zones) on a single electrophoretic gel plate. The purpose of utilizing multiple sample areas is to enable detection separately of total serum protein, and various proteins such as the immunoglobin heavy chains IgG, IgM, IgA and light chains Kappa and Lambda, or other proteins whose presence or absence may be of importance in medical diagnosis. As known in the prior art, various antisera (i.e., fluid containing the antibody) such as IgG, IgM, etc., are deposited on the appropriate zones and permitted to react with the antigen in the sample. The term "incubation" refers to the time interval during which the antisera and antibody are in contact such that a reaction may occur.
Prior to the present invention, in order to determine the effectiveness of the chemicals, various techniques were employed. U.S. Pat. No. 5,137,614, issued on Aug. 11, 1992 to Golias, which is hereby incorporated by reference, is directed to a control system including a template for verifying the effectiveness of the chemicals utilized in the immunofixation electrophoresis procedure. This is accomplished without the need to interrupt patient specimen evaluation when chemicals are replenished, since the chemical utilized on the specimens are also utilized in the control test. The control system verifies that the chemicals have retained their lability.
U.S. Pat. No. 3,844,918, issued on Oct. 29, 1974 to Crawley, which is hereby incorporated by reference, is directed to a template which includes an aperture through which serum is received. The template is placed on a mold having an extended portion which passes through the aperture. Gel is coated on one surface of the template. When the gel molds around the portion extending through the aperture, the mold is removed from the template. The template is left with a small cavity in which the serum is placed.
U.S. Pat. No. 5,403,456, issued on Apr. 4, 1995 to Bellon, which is hereby incorporated by reference, is directed to a mask which includes an orifice through which liquid is deposited on the zone of the gel, and a slit through which excess liquid is withdrawn from the zone of the gel after the incubation step. In practice, the mask is placed in close proximity to, but spaced apart from the surface of the gel, the liquid is deposited through the mask onto the gel, the mask is maintained in its relative position during the incubation step, and, thereafter, excess liquid is withdrawn through the mask. Then, of course, the mask, is removed.
Applicants have discovered that use of the type of device described in the Bellon patent has certain drawbacks. For example, the fluid sample is exposed to ambient conditions and thus partial evaporation may occur. This will change the concentration of the sample and affect quantitative analysis. Similarly, the antisera are exposed to ambient conditions during incubation, again leading to partial evaporation, change in concentration, and sensitivity errors. In addition, ambient conditions may otherwise affect the integrity of the fluid.
After the electrophoretic separation step, the entire reaction zone must be covered with the antiserum since the antigen (i.e., protein fraction) resolution may have occurred virtually at any position along the reaction zone. If the entire zone is not covered, the antibody-antigen reaction may not occur; thus covering the entire zone is important for qualitative purposes. Furthermore, there must be sufficient antiserum deposited to insure that all the antigen will react, otherwise the quantitative aspect of the test will be compromised. Thus it is conventional to apply excess amounts of antiserum. However, Applicants have discovered that prior art techniques and apparatus fail to properly control the flow of the antiserum. Thus, for example, in IFE, or any other procedure, where various reagents are deposited on distinct zones of the same gel, the use of excess amounts of reagent can cause the reagent to "overflow" from one zone onto an adjacent zone. Another problem is that if the reagents in two adjacent zones each "overflow" their respective zones, the reagent which "overflows" one zone can contact the reagent which "overflows" from an adjacent zone, resulting in "cross-contamination" between zones or otherwise compromising the test results for one or more zones.